Garnet vs Varnish Cache

Garnet is a free remote cache-store from Microsoft Research for self-hosted use on Linux, macOS, and Windows. It uses RESP and works with many unmodified Redis clients, including StackExchange.Redis; documented libraries also include Jedis, Redisson, redis-py, node_redis, and go-redis. Its data APIs cover strings, lists, hashes, sets, sorted sets, geo operations, HyperLogLog, bitmaps, ACLs, pub/sub, transactions, and Lua scripting. Garnet can store datasets larger than memory on local or cloud storage and supports checkpointing and recovery. Multi-node mode provides sharding, state migration, and replication. Developers can register C# data structures and read-modify-write operations through its custom operator framework. TLS/SSL and password-based RESP authentication are supported. DiskANN vector database support and Bf-Tree range indexes are marked preview. Garnet is MIT-licensed, but is not intended as a fully compatible Redis replacement and does not support Redis modules. The self-hosted plan is free; you manage infrastructure, updates, and operations. The managed Azure Cosmos DB Garnet Cache is in expanded Private Preview, with no price listed.

Varnish Cache is a reverse caching proxy for Linux and self-hosted deployments. It serves cached responses from memory and sends other requests to origin servers. Its caching policy is defined in Varnish Configuration Language (VCL), which compiles to native code. Cached objects follow standard HTTP cache headers and leave the cache when they expire. Varnish supports TLS termination within the process and TLS connections to dynamic origin backends. It includes varnishlog for structured logging and varnishstat for metrics, and offers official container images and a Kubernetes Helm chart. Installation guidance covers Debian, Ubuntu, Red Hat Enterprise Linux, and compatible distributions. Varnish modules add functions callable from VCL. Its security guide describes controls at the command-line, CLI, VCL, and HTTP request levels. The free plan costs nothing. One limit to account for: Varnish avoids caching data when it cannot determine that doing so is safe, and applications may need configuration changes to reach a high cache hit rate.